The STS-74 flight crew walks out of the Operations and Checkout Building on their way to conduct Terminal Countdown Demostration Test (TCDT) exercises while aboard the Space Shuttle orbiter Atlantis at Launch Pad 39A. They are (from right): Mission Commander Kenneth Cameron; Pilot James Halsell; and Mission Specialists William McArthur Jr., Chris Hadfield, and Jerry Ross (back). Hadfield is an international mission specialist representing the Canadian Space Agency. This flight will feature the second docking of the Space Shuttle with the Russian Mir space station. Docking operations will be conducted with the Russian-built Docking Module attached to the end of the Orbiter Docking System (ODS) located in Atlantis payload bay. The DM will be left attached to the Mir when Atlantis undocks. This module will serve as a means to improve future Shuttle-Mir docking operations.